The present disclosure relates to an electronic governor and control system for a portable, residential, or small business generator system.
Typical generator systems employ direct drive transmissions to couple an engine to an alternator. Direct drive systems typically fix the engine speed at 3,000 rpm (50 Hz) or 3,600 rpm (60 Hz), depending upon the required output current frequency. Due to the nature of direct drive transmission, such systems are inefficient and excessively noisy during low load operation. Some generator systems employ an inverter to allow the engine to operate at speeds that are proportionate to the power demand. A generator is rotated at a variable speed and its output is converted into direct current. Then, the inverter creates a sinusoidal output from the direct current at the desired output voltage and frequency (e.g., 120 VAC, 60 Hz). However, inverters are both complex and expensive.
Presently, continuously variable transmission (CVT) pulley systems are available for coupling the output of an engine to an alternator. One type of coupling system is shown in U.S. Patent Publication No. 2009/0236860, the disclosure of which is incorporated herein by reference. In the CVT systems described in the cited reference, a governor monitors the rotational speed of the alternator through an rpm sensor having a stationary permanent magnet that senses the passing of each tooth on a tooth wheel coupled to the rotor shaft. Based upon the signal from the rpm sensor, the governor adjusts the throttle position of the engine to maintain a constant alternator speed. Although this type of system has proven effective, the cost of the various components used to sense the alternator rotor speed increase the overall cost and complexity of the generator set.